Endoscopes have attained great acceptance within the medical community since they provide a means to perform procedures with minimal patient trauma while enabling the physician to view the internal anatomy of the patient. Over the years, numerous endoscopes have been developed and categorized according to specific applications, such as cystoscopy, colonoscopy, laparoscopy, upper GI endoscopy and others. Endoscopes may be inserted into the body's natural orifices or through an incision in the skin.
An endoscope is usually an elongated tubular shaft, rigid or flexible, having a video camera or a fiber optic lens assembly at its distal end. The shaft is connected to a handle which sometimes includes an ocular for direct viewing. Viewing is also usually possible via an external screen. Various surgical tools may be inserted through a working channel in the endoscope to perform different surgical procedures.
In conventional endoscopes, the optical head, which is used to view the interior of a body cavity or lumen, such as a lower digestive track, is deployed in the front section of the endoscope that is inserted in the body. The optical head normally includes at least an illumination means to illuminate the object, an objective lens system, and a sensor array. The lens assembly in typical optical heads further comprises a lens housing and a barrel that supports the lenses. Current GI scopes use metal components for the housing and for other sections in the optical head that support the lenses. Commonly used metals are stainless steel and brass. They are machined into a required shape and fitted inside the scope. The metal components may be coated, blackened, polished, and treated in different ways. However, over time, small parts of these components wear out and the resulting particulate debris may interfere with, and get sensed by, the sensor. Burrs and other particles falling off from the lens housing components find their way onto the optical sensor. These particles show on the imaging monitors used by the physician. Additionally, machining metal components results in slight differences in shape and/or size with each machine, resulting in inconsistent components. The barrels used in lens assemblies often include two separate components comprising the barrel itself and an adapter within the barrel to hold the lenses. The outer surface of the barrel is typically threaded to match a threaded inner surface of the lens holder. The barrel is limited to spiral movement within the lens holder along these threaded surfaces. The threaded surfaces introduce further points for the creation burrs and particles as described above.
Therefore, there is a need in the art for endoscope components, and specifically lens assembly components, that are manufactured with consistency and, once embedded inside the scope, remain clean and/or are easy to clean. There is also a need for a lens assembly comprising a single barrel component having a formed inner surface for seating lenses, thereby eliminating the requirement of an adapter and reducing the overall number of lens assembly components. Such a lens assembly would also include a smooth barrel outer surface and a smooth lens holder inner surface to allow for greater freedom in movement of the barrel relative to the lens assembly and to reduce the likelihood of particles falling off either component and onto the optical sensor. There is also a need for endoscopes, such as colonoscopes, gastroscopes, bronchoscopes, and the like, that enable efficient packing of all necessary lens elements in the tip section while maintaining their functionality.